yes, there is a tool to pull fly wheel.
Or just do, what I've been doing for years ,SEE PIC
remove crank nut.
using a flat screwdriver cut edge of case rim,as in pic, so a flat screwdriver can fit behind flywheel,
with "LIGHT" pressure behind flywheel,(Don't pry on it hard) "LIGHTLY TAP" on center of FLYWHEEL >>>NOT THE CRANK<<< and flywheel should pop right off real easy.
as for the KEYWAY it's on the crank that the nut was on, it's a little 1/2 moon looking piece of metal that sits flat side up ,that is what keeps the flywheel in line with the crank, look at the inside of flywheel crank hole at the notch if it looks worn out(not straight) you have a major problem.
Now, when reinstalling flywheel, I make sure the piston is TDC and and points are open on high point of flywheel ,line up keyway to flywheel and slide on to crank Make sure it's on correct b-4 you install crank nut.Good Luck!